Wikileaks.org now points to a mirror of the site, mirror.wikileaks.info, hosted by Webalta, a blackhat ISP linked to a company called Heihachi Ltd, according to Spamhaus. The .org URL has been WikiLeaks' main web address since its launch in 2006.

"Spamhaus regards the Russian Webalta (also known as Wahome) host as being "blackhat" - a known cybercrime host from whose IP space Spamhaus only sees spamming, malware/virus hosting, phishing and other cybercriminal activities," the anti-spam organisation said on Tuesday evening.

The warning follows similar concerns raised by Trend Micro, which also runs a spam-blocking list.

Both firms said that whatever political view one takes of the ongoing WikiLeaks saga, the site's administrators should take more care over the company it keeps.

Ironically, the judgment of an investigator that Vladimir Putin's Russia is a "virtual mafia state" has been one of the highest-profile disclosures from the US embassy cables so far released by Wikileaks.

"The fact that recently some unknown person or persons decided to put a Wikileaks mirror on IP address 92.241.190.202 should raise an alarm; how was it placed there and by whom," said Spamhaus.

"Our concern is that any Wikileaks archive posted on a site that is hosted in Webalta space might be infected with malware... Spamhaus takes no political stand on the Wikileaks affair."